Spiral steel pipes are made from coiled steel strips through cold rolling and forming, and welded using the automatic double-wire double-sided submerged arc welding process. The main production process is as follows:
(1) Raw materials, including coiled steel strips, welding wire, and flux, undergo rigorous physical and chemical inspections before being introduced.
(2) The ends of the steel strips are butt-welded using single-wire or double-wire submerged arc welding, with automatic submerged arc welding for welding repair after coiling.
(3) Before forming, the steel strips undergo straightening, edge trimming, edge planing, surface cleaning, and pre-bending treatments.
(4) The pressure of the oil cylinders on both sides of the conveyor is controlled by an electric contact pressure gauge to ensure the smooth transportation of the steel strips.
(5) External or internal control roller forming is adopted.
(6) Weld gap control devices are used to ensure that the gap between the welds meets welding requirements, with strict control over pipe diameter, misalignment, and weld gap.
(7) Both internal and external welding are carried out using Lincoln electric welding machines for single or double-wire submerged arc welding to achieve stable welding specifications.
(8) The welded seams are inspected by online continuous ultrasonic automatic flaw detectors to ensure 100% coverage of non-destructive testing of spiral welds. If defects are detected, automatic alarms are triggered, and marks are sprayed for the production workers to adjust process parameters and eliminate defects in a timely manner.
(9) Steel pipes are cut into individual pieces using plasma cutting machines.
(10) After being cut into individual pipes, the first three pipes of each batch undergo strict initial inspection procedures to check the mechanical properties, chemical composition, fusion conditions of the welds, surface quality of the pipes, and undergo non-destructive testing to ensure that the pipe manufacturing process is qualified before being formally put into production.
(11) Parts of the weld seams with continuous ultrasonic flaw detection marks undergo manual ultrasonic and X-ray re-inspection. If defects are confirmed, they are repaired, re-inspected by non-destructive testing, and confirmed to be eliminated.
(12) The weld seams of the welded joints and the D-shaped joints intersecting with the spiral weld seams are all inspected by X-ray television or film.
(13) Each pipe undergoes a hydrostatic test, with radial sealing used for pressure. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device, with test parameters automatically printed and recorded.
(14) Mechanical processing of pipe ends ensures accurate control of end verticality, bevel angle, and blunt edge.
Storage Techniques for Spiral Steel Pipes: Ensuring stable improvement in the quality of spiral steel pipe products is a powerful guarantee for increasing the company's economic benefits. Over the years, we have consistently prioritized product quality, strengthened quality supervision and feedback, and controlled quality risks in the process. The pass rate of our products in various industrial product quality spot checks in Tianjin has been 100%. High-quality products have enabled our company to obtain a series of certificates, including the APISPEC5L product certification issued by the American Petroleum Institute. "This has provided an important pass for sales personnel to break through major customers and further expand export markets."
(1) The site or warehouse for storing spiral steel pipe products should be selected in a clean and dry place with smooth drainage, away from factories and mines that produce harmful gases or dust. Weeds and all debris should be cleared from the site to keep the steel clean.
(2) Corrosive materials such as acids, alkalis, salts, and cement should not be stacked together with steel materials in the warehouse. Different types of steel should be stacked separately to prevent confusion and corrosion.
(3) Large-section steel, rails, steel plates, large-diameter spiral steel pipes, forgings, etc., can be stored in the open air.
(4) Medium and small-section steel, wire rods, steel bars, medium-diameter steel pipes, steel wires, and steel wire ropes can be stored in well-ventilated sheds, but must be covered and padded underneath.
(5) Some small steel materials, thin steel plates, steel strips, silicon steel sheets, small-diameter or thin-walled spiral steel pipes, various cold-rolled and cold-drawn steel materials, as well as high-priced and easily corroded metal products, can be stored in the warehouse.
